<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8" />
    <title>2.姓名案例_计算属性简写</title>
    <!-- 引入Vue -->
    <script type="text/javascript" src="../js/vue.js"></script>
</head>

<body>
    <!-- 准备好一个容器-->
    <div id="demo">
        姓：<input type="text" v-model="firstName"> <br /><br />
        名：<input type="text" v-model="lastName"> <br /><br />
        全名：<span>{{fullName}}</span> <br /><br />
    </div>
</body>

<script type="text/javascript">
    //阻止 vue 在启动时生成生产提示。
    Vue.config.productionTip = false
    const vm = new Vue({
        el:'#demo',
        data:{
            firstName:'zhang',
            lastName:'san',
        },
        computed: {
            // 简便写法
            fullName(){
                console.log('fullName-get');
                const {firstName,lastName} = this
                return firstName[0].toUpperCase() + firstName.slice(1) + '_' + lastName
            }
        }
    })
</script>

</html>